Ball point pen



` INVENTOR FRANCIS E. GRUBER BY @i ,M44 TORNEY F. E. GRUBER BALL PO INTPEN Feb. 1, 1949.

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Patented Feb. 1, 1949 BALL POINT PEN Francis E. Gruber, St. Paul, Minn.,assigner to 'i Brown et Bigelow, St. Paul, Minn.

Appunti@ December 22, 1945, serial No. 636,790

' This invention relates to a fountain pen Wherein the rink used thereinis of a, viscousfnature and tends to travel through the ink chamber bycapillary. attraction tothe writing tip. The writing tip is in the formof'a ball which rotates in a socket. The viscous ink is picked up by thewriting ball and carried by capillary attraction from the reservoir ontothe ball and from the ball to the surface on which the pen is writing.

A feature resides in providing` aunit ink reservoir of a tubular nature,the body of the reservoir being in the form of helical coils of hollowtubing and to the forward end of the unit I attach the writing. endofthe pen which supports the ball bearing freely rotatable inY a socketon" the extreme outer end of the unit.

A feature resides inproviding a fountain pen with a replaceable inkchamber unit and writing end which are connected=together as a completeunit and which may be replaced with a new unit whenever it is desired.The ink used in my pen is not of the freely iiowing type like thatordinarily used in fountain pens employing a pen point. The ink is of aviscous nature with a surface tension so as to be attracted by capillaryaction causing the ink to travel toward the smaller opening in thechamber while atmospheric air is admitted to the larger or rear end ofthe unit. It is desirable that a complete volume of ink extend into thewriting tip and it is irnportant that the ink contact the bali withoutair space between the ball and the ink. The iiow of the ink is limitedby the surface tension and the ball acts to enhance the trave1 of theink to the writing tip as the ink is used up in writing.

With a pen of this character, the writing cperation is smooth and freeon all sides so that the pen may be rotated into any position. Thewriting of my pen may be characterized as being smooth and free like thewriting with a pencil. The ball bearing writing tip rolls freely overthe surface being written upon and discharges the ink onto the surfacein a smooth line.

A feature resides in providing a propelling and repelling means for theink unit and/writing tip which is adapted to be operated by rotating therear end of the pen which operates a screw core member threaded to theinner surface of the coils of the ink reservoir and thus the inkreservoir and writing tip as a unit are propelled into writing positionor withdrawn into the casing of the pen so as tc conceal the writing endof the pen without need of a cap for covering the writing end when thepen is not in use.

These features together with other details and 3 Claims. (ci. 12o-42.03)

' objects of the invention will be moreY fully. and

clearly hereinafter set forthinthe specification and claims.

Figure 1 illustrates a longitudinal section throughmypen. f I g Figure 2is a similar view to Figure 1 with a portion ofthe pen 4casing brokenaway and a portion of the ink reservoir illustratedin section with therear end of the pen. I

The pen A is formed with an outer casinghaving Aa removable writing tipH3, a barrel portion! i, and a rotatable end cap member it. The clip itis mounted on thecap i2 by thehead it which is threaded at i5 tothe capl2. H

The head I2is adapted 4to be held rotatable -to the rear end of thebarrel il by the spring sleeve it which operates between the collarscarried by the head i2 and which provides a frictional engagement withthe inner sleeve ll'in the rear end of the casing or barrel I I. j Y- av/ The head l2 is provided with an extended core member i8 which isformed with threads i9 on the inner end of the same. The end it and thethreads I 9 are rotated when the cap l2 is rotated. The cap l2 is formedwith an elongated sleeve 2G which rotates with the cap and the clip I3and at the same time the threads IS are rotated.

The ink reservoir unit B is formed by a hollow tubular member 2l whichis formed with a series of coils 22, the forward end of the tube 2i isconnected to the writing tip 23 and in the eX- treme forward end of thewriting tip E3 I mount a ball bearing 2t which is the writing end of theunit B and which rotates freely in the writing tip 23.

The ink reservoir unit B is removable with the writing tip `23 and theball 2B so that a new unit B may be inserted in the casing of the barrelii whenever it is desired.

The hollow tubular reservoir B is adapted to be i'llled with a viscousink having a surface tension which allows the ink to be extended throughthe small passageway 25 in the writing tip 23 to the ball 2t. When theunit B is filled with the ink the last two or three coils at the rear ofthe same are left empty to provide an air chamber in the rear end of theink unit B which allows for expansion of the ink without the same oozingfrom the chamber. The rear end 26 of the coils 22 extends outlongitudinally as illustrated in Figures 1 and 2 and is adapted tocontact the rib 21 formed on the inner sleeve l'i to hold the unit Bagainst rotation in the barrel l i. The threads I9 engage the coils 22so that when the head I2 3 is rotated and the unit B is held againstrotation by the rib 21, the entire unit B with the writing tip 25 andball 24 is moved longitudinally for- WardV or backward Within the casingof the pen A.

When the writing ball 24 and the unit B are in the position illustratedin Figure 1, the pen A is in operative position with the ball 24 exposedout of the writing end I of the casing of the pen.

When the pen is not desired for `use the cap l2 may be rotatedk tooperate the threads i 9 to draw the unit B into the barrel or casing ofthe pen A as illustrated in Figure 2. This operation conceals theWriting ball 24 in the tip lll.

The viscous ink used in my pen is of a nondrying nature, therefore a capis not required for the pen, however, it is desirable that the pen ball24 be drawn into the Vtip end 10 so as to protect the user of the penfrom getting inl: onto articles when the pen is not in use.

The unit B is moved in its entirety with the writing ball 24`by turningYthe cap l2k which causes the threads I S tomove the unit B forward orbackward as may be desired. Figure 2 shows the unit B retracted into thebarrel of the pen A and with the writing ball 24 protected Within thetip l0. The alternative form illustrated in Figure 3 shows the outerpart of the tube 28 threaded at 29 so as to engage with the threadedcollar 30 when the cap I2 is rotated.

I claim:

1. A fountain pen comprising an ink unit formed of a hollow tube, aseries of coils formed inthe body of said ink reservoir adapted toprovide the main part of the reservoir, a tubular ior- 4Ward endprojecting Vas a-portion oisaid ink-unit, Va ball Writing tip mounted inthe forward end of said ink reservoir unit, a casing for enclosingsaidunit and adapted to support the same 'slidable therewithin, a rotatablecap for the `rear of said casing, and a threaded core member operated bysaid cap to threadedly engage said ink unit to move the samelongitudinally in said casing to conceal or expose said writing ball onthe forward end of said ink reservoir unit.

2. A fountain pen including a casing, a replaceable ink unit, saidcasing being separable to permit a new ink unit to be inserted therein,said ink unit being formed of a hollow tube with the body portionthereof formedinto a series of helical coils positioned adjacenteachother, the rear end of said unit being open to the outer atmosphere,the forward end of said unit having a writing ball rotatably anchoredtherein, and means for moving said ink unit in said casing to expose andconceal said writing ball by a threaded engagement of said helicalcoils.

3. `A fountain pen including a casing, a removable ink unit supportedwithin said casing, said ink unit being formed of a hollow tube, aseries of coils formed in said tube adjacent each other to form the mainAbody portion of said. unit, a writing ball bearing :anchoredon theforward ,end of said unit and threaded core means for engaging the rearof said unit to move said unit bodily backward or forward within saidcasing.

FRANCIS E. GRUBER.

REFERENCE S CIT ED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Great Britain Dec. 4, 1945

